<?php


namespace application\core;


class VerificationCode
{
    private $charset = 'abcdefghjkmnprstuvwxyzABCDEFGHJKMNPRSTUVWXYZ23456789';

    private $code;

    private $codeLen = 4;

    private $width = 200;

    private $height = 60;

    private $img;

    private $font = APP_PATH . 'resources/font/elephant.ttf';

    private $fontsize = 32;


    // 生成随机码
    private function createCode($id)
    {
        $_len = strlen($this->charset) - 1;
        for ($i = 0; $i < $this->codeLen; $i++) {
            $this->code .= $this->charset[mt_rand(0, $_len)];
        }
        //将验证码保存至redis
        if (REDIS_ENABLE) {
            $redisUtil = RedisUtil::instance();
            //设置一个15分钟有效的redis key
            $redisUtil->setex($id, 15*60, $this->code);
        } else {
            $this->code = "";
        }
    }

    // 生成背景
    private function createBg()
    {
        $this->img = imagecreatetruecolor($this->width, $this->height);
        $color = imagecolorallocate($this->img, mt_rand(157, 255), mt_rand(157, 255), mt_rand(157, 255));
        imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, $color);
    }

    // 生成文字
    private function createFont()
    {
        $_x = $this->width / $this->codeLen;
        for ($i = 0; $i < $this->codeLen; $i++) {
            $fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imagettftext($this->img, $this->fontsize, mt_rand(-30, 30), $_x * $i + mt_rand(1, 5), $this->height / 1.4, $fontcolor, $this->font, $this->code[$i]);
        }
    }

    // 生成线条、雪花
    private function createLine()
    {
        // 线条
        for ($i = 0; $i < 6; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);
        }
        // 雪花
        for ($i = 0; $i < 100; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
            imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width), mt_rand(0, $this->height), '*', $color);
        }
    }

    // 输出
    private function outPut()
    {
        //header('Content-type:image/png');
        //imagepng($this->img);

        //echo "<img src=$image_data_base64>";
        //imagedestroy($this->img);
    }

    // 获取验证码
    public function getCode($id): string
    {
        ob_start();
        $this->createCode($id);
        $this->createBg();
        $this->createLine();
        $this->createFont();

        imagepng($this->img);
        $image_data = ob_get_contents();
        ob_end_clean();
        imagedestroy($this->img);
        return "data:image/png;base64," . base64_encode($image_data);
    }
}